The present invention relates to a gas-filled circuit breaker, particularly to a gas-filled circuit breaker having a driving force for operating contacts being supplied from the outside of the breaker.
Generally, a gas-filled circuit breaker has a pair of contacts in a hermetically sealed container filled with an arc-extinguishing gas, and an operating device for driving the pair of contacts to be closed and opened is arranged at the outside of the hermetically sealed container. Therefore, a driving force transmission mechanism between the operating device and one of the movable contacts includes a hermetically sealed connecting mechanism for transmitting the driving force with maintaining the hermetic seal of the container.
The conventional hermetically sealed connecting mechanisms such as those shown in FIGS. 5a, 5b and 10 include a rotational seal structure or a linear seal structure. Typical conventional seal structures are illustrated at 71, 72 in FIGS. 5b and 10. The rotational seal as shown in FIG. 5a is disclosed by Publication of Laid-open Japanese Patent Application 61-284014. In FIG. 5a, a hermetically sealed container 1 with an end plate 1b is filled with the arc-extinguishing gas and receives an interrupter portion 12 including a pair of contacts. A movable part of the interrupter portion 12 is connected through an insulated operating rod 15 to an interior lever 16 fixed to a rotational shaft 2. The rotational shaft 2 extends through a side wall of a case 17 fixed to the end plate 1b with a hermetic seal between the shaft 2 and the side wall, and has an exterior lever 4 at the outside of the case 17. The exterior lever 4 is connected to a driving shaft 18 of an operating device 13 with a dashpot device 10 and a closing spring 11. When the interrupter portion 12 is operated by the operating device 13 to be opened or closed, the rotational shaft 2 is rotated while keeping the hermetic seal of the case 17 and of the hermetically sealed container 1 sealed with a gasket or the like.
In the conventional gas-filled circuit breaker including the linear seal structure as disclosed by Publication of Laid-open Japanese Utility Model Application 52-156973, the driving rod 18 is coaxially connected to the insulated operating rod 15, and extends through a wall surface of the case 17 while keeping the hermetic seal between the driving rod 18 and the case 17.